A cellulose acetate film is mainly used to provide optical isotropy. However, an optical compensation sheet and a retardation film of a liquid-crystal display device need to have high optical anisotropy, and the film is subjected to stretching-treatment or a retardation controlling agent is added to provide high optical anisotropy.
However, a cellulose acetate material that is difficult to stretch does not provide a high retardation required for a retardation film by only stretching, and the retardation controlling agent needs to be added.
However, problems such as bleeding occur while providing the retardation, and there is a need to find a solution to the above problems.